I'm not entirely hooked yet.... I think the problem here was the forced tightness because of length. I don't know if she/he meant that nobody ever knows about the watcher or nobody ever watches the protagonist.

Kinda there. Watch out for the was/were VERB-ing giving way to passive voice. Try to use VERB-ed instead whenever possible. This gives me the feel that this guy watched the MC in a way that no one could know he watched her. Hmmm.